docs: add a logging handler example

examples/logging_handler.py

@@ -0,0 +1,47 @@
+"""
+Show the usage of influx with python native logging.
+
+This is useful if you
+* want to log to influx and a local file.
+* want to set up influx logging in a project without specifying it in submodules
+"""
+import datetime
+import logging
+import time
+
+from influxdb_client import InfluxLoggingHandler, WritePrecision, Point
+
+DATA_LOGGER_NAME = '…'
+
+
+def setup_logger():
+    """
+    Set up data logger with the influx logging handler.
+
+    This can happen in your core module.
+    """
+    influx_logging_handler = InfluxLoggingHandler(url="…", token="…", org="…", bucket="…",
+                                                  client_args={'arg1': '…'},
+                                                  write_api_args={'arg': '…'})
+    influx_logging_handler.setLevel(logging.DEBUG)
+
+    data_logger = logging.getLogger(DATA_LOGGER_NAME)
+    data_logger.setLevel(logging.DEBUG)
+    data_logger.addHandler(influx_logging_handler)
+    # feel free to add other handlers here.
+    # if you find yourself writing filters e.g. to only log points to influx, think about adding a PR :)
+
+
+def use_logger():
+    """Use the logger. This can happen in any submodule."""
+    # `data_logger` will have the influx_logging_handler attached if setup_logger was called somewhere.
+    data_logger = logging.getLogger(DATA_LOGGER_NAME)
+    # write a line yourself
+    data_logger.debug(f"my-measurement,host=host1 temperature=25.3 {int(time.time() * 1e9)}")
+    # or make use of the influxdb helpers like Point
+    data_logger.debug(
+        Point('my-measurement')
+            .tag('host', 'host1')
+            .field('temperature', 25.3)
+            .time(datetime.datetime.utcnow(), WritePrecision.MS)
+    )